Bob,

Recently, Dragon Ball Z was added to Netflix. I watched for a bit and was shocked to realize it was a 1989 production. Moreover, it didn’t start from the beginning of the story but from the scene where Gohan is born and the Saiyans arrive on Earth. I was taken aback and could hardly stop myself from sighing at how time flies.

Getting back to the main topic, handling cryptocurrency inheritance in a decentralized way is a principle much like Dragon Ball: the private key is Shenron, who guards your assets; the seven Dragon Balls you need to collect to summon Shenron are what I’m about to introduce as multi-share backups. You giving one of the Dragon Balls to your son, Frank, is just like Grandpa Gohan leaving the four-star Dragon Ball for Goku. And the unique skill of the Namekians to create the Dragon Balls is the SLIP-39 standard.

You may have heard that ever since Bitcoin started naming community proposals and standards with BIP (Bitcoin Improvement Proposal) + a number, the industry has followed this custom. The most well-known are EIPs (Ethereum Improvement Proposal), such as EIP-20, which became the ERC-20 standard upon adoption, and EIP-4337, which defines account abstraction. In SLIP-39, the “SL” stands for SatoshiLabs, the manufacturer of Trezor. This improvement proposal numbered 39 is a standard for disassembling and reassembling a private key, known as Shamir’s secret sharing or Shamir backup. In recent years, SatoshiLabs has renamed it to multi-share backups, likely considering it more approachable. The names are different, but technically, they are the same thing.

It’s great that your Safe 5 arrived so quickly; you can now perform the first activation. You only need to activate it once, so why do I say “first”? In contrast to the idea that “life has no take-twos,” I suggest you activate, wipe, and reactivate your Safe 5 at least a few times. It would be best to have Alice go through the process with you as well. For the first activation, don’t overthink it or be too cautious. As long as you don’t deposit a large sum of money, it’s okay to make mistakes. In fact, making mistakes is even better—the sooner, the better.

Currently, the vast majority of cold and hot wallets still rely on a single set of mnemonic words for account recovery. If you lose the words, you lose your assets. It’s just as frightening as when you first started in 2018; not much has progressed. In this regard, Trezor is more advanced, as it already defaults to using multi-share backups when creating an account.

Although I used Dragon Ball as a metaphor, multi-share backups don’t have to be seven shares, and you don’t necessarily need all of them to summon Shenron. Instead, you can set your own m-of-n scheme, where ‘n’ is the total number of shares, and ‘m’ is the number of shares required to summon Shenron. When both parameters are set to 7 (a 7-of-7 scheme), it becomes a true seven Dragon Balls setup. Conversely, when m=n=1 (a 1-of-1 scheme), the effect is no different from a traditional mnemonic phrase. Obviously, both extremes lack resilience. A more ideal approach is to set m < n, such as 2-of-3 or 3-of-5. This way, no single guardian can summon Shenron alone, and even if some Dragon Balls are lost, you can still summon Shenron as long as you have more than half.

This is why I asked you to do some “homework” and think about which friends are the most reliable, with various conditions attached. The ideal setup would be to find seven friends who are trustworthy, security-conscious, located in different parts of the world, and who do not know each other (or at least not well). You would then give them the shares of a 4-of-7 setup and ask them to give the Dragon Balls to your wife, Alice, after you pass away. It’s a bit demanding, don’t blame me. Decentralization is a spectrum. I’m not saying you must go to this extent, but merely illustrating the aspects you need to consider to achieve the strongest resilience.

As the saying goes, we learn from mistakes (aka it’s most enjoyable to watch others fail). Rather than listing best practices, let’s look at some negative examples:

• Having a few high school classmates as guardians. One day, they have a reunion dinner, discover they are all guardians, and out of curiosity, summon Shenron to see how many bitcoins you have…

• Asking family and friends with 100% integrity but 50% security awareness to be guardians, who then store the “Dragon Ball” in plain text on a Google Drive that gets hacked.

• Finding several friends who don’t know each other but all live on the same island nation to be guardians. Unfortunately, one day an earthquake strikes, triggering a tsunami.

• Having several of your oldest and closest friends as guardians. The choices are too predictable, and powerful authorities harass them, using any means necessary to coerce them into handing over the Dragon Balls.

• Finding friends who are reliable, security-conscious, don’t know each other, and currently live in places like the UK, Australia, the US, and Canada. Then, after a social movement, you discover that several of them are on the opposite side of the political spectrum…

Fortunately, this is a private letter between us. I wouldn’t want to list these bloody but very real examples in a public article. In short, you should now understand the considerations for choosing your Dragon Ball guardians, or conversely, what to avoid. I don’t have, nor should I have, any suggestions on who they should be. I only know that I should not be one of them. Please don’t tell me who you choose, and don’t tell anyone else—not even your wife Alice. All that matters is that the guardians know when and how to contact Alice.

Perhaps I sound like I’m exaggerating or being an alarmist, but I feel a responsibility to adopt the most serious attitude and assume the worst-case scenario. The mechanism for decentralized inheritance is not complicated to operate. Compared to a step-by-step tutorial on which button to press or which function to use, it is far more important to ensure that the guardians treat this responsibility with the seriousness it deserves. We have both used cryptocurrency for years and truly believe in decentralized mechanisms, or more fundamentally, in mathematics. But most people don’t think this way, and that likely includes the people you will approach. If we don’t explain the importance to the guardians with extreme seriousness, they might take it lightly, fail to realize its gravity, and think you’re just being hysterical and overthinking things.

Those of us who used to live in a civilized society (perhaps the past tense only applies to me) are like sheltered animals, accustomed to a baseline of trust between people. If we cannot learn the importance of being trustless, we will die a horrible death once exposed to the dark forest. Ugh, I sound even more alarmist, but what I’ve said is, sadly, so true.

I’ve written too much. Go ahead and activate your Trezor Safe 5. Generate a new wallet account, start simply by setting up a 2-of-3 multi-share backup to create three Dragon Balls. Let’s assume you give them to Carol, Dave, and Eve. Then, practice using any two of them to summon Shenron and restore the account on another Safe 5.

I’ll wait for you to share your experience. Let’s talk again next week.

kin
2025.09.03